Ship has to listen to money-lenders (6)
I believe the answer is:
sharks
'money-lenders' is the definition.
('shark' can be a synonym of 'money-lender')
'ship has to listen' is the wordplay.
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'has' indicates putting letters inside.
'to listen' becomes 'hark' (harking is a kind of listening).
'ss' going around 'hark' is 'SHARKS'.
'to' is the link.
(Other definitions for sharks that I've seen before include "Large carnivorous fish" , "Feared fishes, may be basking or hammerhead" , "Voracious sea fish" .)